It is all to do with health and safety.
A number of years ago, we had very heavy snow and when I got to school, (it took over an hour to walk there, although I lived locally), I discovered my colleague and I were the only two teachers there, as most staff couldn't get there.
We had over 100 excited, soaking wet, cold children contained in the school hall, with just two of us and a pupil support assistant, which of course was, from a health and safety point of view, very risky.
Many had walked on their own, without parents, so we couldn't even ask the parents to take them back home. Neither could we leave them to ring round parents, as we had some very challenging children, who needed supervision.
It was a very stressful situation.
We really have to look at the bigger picture. The priority is keeping everyone safe.